LRRC4 (Leucine Rich Repeat Containing 4): LRRC4 (Leucine Rich Repeat Containing 4) is a protein mainly expressed in the brain and involved in neural development. It plays a role in the formation and maintenance of the nervous system, as well as in neural cell adhesion and signalling. LRRC4 has been studied in relation to brain tumours, especially gliomas, making it a key focus in neurobiology and cancer research.